Cognition in pregnancy and the first year post-partum.

A longitudinal study measured the performance of a group of 15 pregnant women on tests of verbal memory, divided attention, and focused attention on four occasions (second trimester, third trimester, 6 weeks post-partum, and 1 year post-partum) while at the same time obtaining self-assessment ratings of these cognitive functions. A group of 14 non-pregnant women was studied at equivalent intervals. The two groups of women did not differ in performance on the objective tests, and there was no change in performance over time except for an improvement in the measure of focused attention from the first to the final testing occasion. However, the self-assessment ratings showed that in the second trimester, the pregnant women rated themselves as more impaired than before compared with the non-pregnant women for all three cognitive abilities. To ensure that this difference was not due to the retrospective nature of the comparison of current with previous cognitive ability, a second longitudinal study compared 25 pregnant and 10 non-pregnant women using daily ratings over a period of 1 week on four occasions during pregnancy and the first year post-partum. Women in the third trimester of pregnancy reported mild impairments in their focused and divided attention ability and their ability to remember what they had read compared with the non-pregnant women. The results show that there are perceived cognitive impairments during pregnancy. It is suggested that these may be the result of mild impairments which are not revealed in objective tests because they can be overcome by conscious effort in short periods of testing. Alternatively, the perceptions may not be based on actual impairments but may result from depressed mood or expectations concerning the effect of pregnancy on cognition.

Childhood amnesia: on answering questions about very early life events.

Twenty five young adults were asked about the events surrounding the birth of a younger sibling which took place when they were under the age of 2 years. Approximately 40% of the participants claimed to have significant memories of the events. The mothers of our participants verified that a majority of their answers were accurate. Comparing the pattern of data with those previously collected (Eacott & Crawley, 1998) suggests that the memories of those who were aged below 2:0 are qualitatively similar to the memories of those who were older at the time of events and dissimilar in type to those who are basing their reports on reconstructions from family knowledge. This finding may be evidence that memories of events that occurred before the age of 2 years are genuine but rare. This conclusion may be useful in assessing theories of childhood amnesia.

The offset of childhood amnesia: memory for events that occurred before age 3.

Adult memory for the events surrounding the birth of a sibling was examined in 69 adults. The authors identified a steep offset for childhood amnesia for this event before the child reaches age 2 1/2 years. The authors also examined the accuracy of information recalled. Although the majority of the answers were accurate, false memories were a consistent feature of the data. Alternative explanations of the authors' data were considered by examining the amount of information an additional 57 adults had about a family birth for which they could have no memory. The pattern of results did not support the view that participants might be unable to differentiate between memories and knowledge about the event.

The use of heuristic strategies in the interpretation of pronouns.

The aim of the two experiments reported here was to distinguish between two heuristic strategies that have been proposed to account for the assignment of pronouns: the subject assignment strategy and the parallel function strategy. According to the subject assignment strategy, a pronoun is assigned to a preceding subject noun phrase, whereas according to the parallel function strategy, a pronoun is assigned to a previous noun phrase in the same grammatical position as the pronoun. These two strategies were tested by examining the interpretation of single object pronouns, first in a reading task and second in an assignment task. In both experiments, there was a strong preference for assigning an object pronoun to the preceding subject noun phrase, thus supporting the subject assignment strategy. However, this was only the case for pronouns that were linguistically ambiguous. When assignment was constrained by gender, there was no effect of either strategy. It is suggested that heuristic strategies are only used in the absence of other strong cues to assignment.

Reference in single sentences and in texts.

This study investigated the comprehension and production of reference terms in both sentences (Experiments 1 and 2) and texts (Experiments 3 and 4) using a sentence completion task. In Experiments 1 and 2, the use of a sentence-level strategy (subject assignment) was investigated. In Experiments 3 and 4, the use of a text-level strategy (topic assignment) was also investigated. There was a clear preference for continuing the sentences by referring to the subjects of the sentences regardless of the availability of gender cues, in both single sentences and in texts. There was also an influence of the topic of each text on both the choice of referent and the type of reference term used. However, the choice of reference term was affected by the number of potential antecedents in the preceding text. Overall, the results suggest that the sentence subject is a salient item in working memory. This salience is increased if the sentence subject is also the textual topic. In addition, it appears that the presence of a pronoun in a text triggers a specific strategy to assign the pronoun to the (salient) sentence subject.